[PATCH] D59832: [LoopRotation] Allow loop header duplication if vectorization is forced

[Florian Hahn via Phabricator via llvm-commits]

fhahn added a comment.

In D59832#1444555 <https://reviews.llvm.org/D59832#1444555>, @Meinersbur wrote:

> This might be a more general problem, other passes might expect a normalized form as well, such as UnrollAndJam and LoopDistribute.
>
> For LoopVectorizer, I am somewhat surprised. It calls simplifyLoop itself (instead of relying on LoopSimplifyPass). Could the same be done for LoopRotation?


I guess it could, but the underlying problem is still the same: as things are currently structured, we have to rotate before we know if vectorization is legal and cannot go back if it is not. Potentially, VPlan allows this sort of thing, by doing those transforms on a separate representation (VPlan IR)


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